Dr. Hope Johnson, Biological Science

Education and Professional Positions

B.S., Cornell University
M.S., Stanford University
Ph.D., Stanford University
Postdoctoral Fellowships, Scripps Institution of Oceanography and The Scripps Research Institute

Current Research Interests

The Johnson Lab is interested in how microbes interact with the environment. We are mainly focused on Mn-oxidizing bacteria which oxidize soluble Mn(II) to insoluble Mn(III,IV) oxides and are important players in the biogeochemical cycling of Mn and other metals. Although we know this group of microbes is extremely important for the health of our planet, we know little about how and why these microbes catalyze this reaction. Our goal is to understand the enzymes catalyzing this reaction and how this reaction may affect cellular physiology. We use the experimental tools of molecular biology, biochemistry, and microbiology to approach this problem. These studies provide insight into biogeochemical cycling and information that may lead to the use of these microbes in the bioremediation of contaminants that threaten our water and natural environment.

Five publications related to current research interests

  1. Anderson, C.R., Johnson, H.A., Caputo, N., Davis, R.E., Torpey, J.W., and Tebo, B.M. Mn(II) oxidation is catalyzed by heme peroxidases in "Aurantimonas manganoxydans" strain SI85-9A1 and Erythrobacter sp. strain SD-21. Applied and Environmental Microbiology 75(12):4130-8. 2009.
  2. Johnson, H.A., Hampton, E. and Lesley, S. A. The Thermotoga maritima Trk potassium transporter – from frameshift to function. Journal of Bacteriology 191: 2276-84. 2009.
  3. Dick, G.J., Podell, S., Johnson, H.A., Rivera-Espinoza, Y., Bernier-Latmani, R., McCarthy, J.K., Torpey, J.W., Clement, B.G., Gaasterland, T., and Tebo, B. M. Genomic insights into Mn(II) oxidation by the marine -proteobacterium Aurantimonas sp. strain SI85-9A1. Applied and Environmental Microbiology 74: 2646-58. 2008.
  4. Johnson, H.A. and Tebo, B.M. In vitro studies indicate a quinone is involved in bacterial Mn(II) oxidation. Archives of Microbiology 189: 59-69. 2008.
  5. Tebo, B.M., Johnson, H.A., McCarthy, J. Templeton, A.S. Geomicrobiology of manganese(II) oxidation. TRENDS in Microbiology, 13: 421-428. 2005.

Recent Student Awards